Golf balls having multi-layer cores are known. For example, U.S. Pat. No. 6,852,044 discloses golf balls having multi-layered cores having a relatively soft, low compression inner core surrounded by a relatively rigid outer core. U.S. Pat. No. 5,772,531 discloses a solid golf ball comprising a solid core having a three-layered structure composed of an inner layer, an intermediate layer, and an outer layer, and a cover for coating the solid core. U.S. Patent Application Publication No. 2006/0128904 also discloses multi-layer core golf balls. Golf balls having multi-layer cores comprising a thermoset center, a thermoplastic intermediate core layer, and a thermoset outer core layer are disclosed, for example, in U.S. Pat. No. 7,708,656 and U.S. Pat. No. 8,262,511. Other examples of multi-layer cores can be found, for example, in U.S. Pat. Nos. 6,071,201, 6,290,612, 6,336,872, 6,379,269, 6,394,912, 6,406,383, 6,431,998, 6,569,036, 6,605,009, 6,626,770, 6,815,521, 6,855,074, 6,913,548, 6,988,962, 7,153,467 and 7,255,656, and U.S. Patent Application Publication Nos. 2009/0181803, 2009/0181799, 2009/0181800, and 2009/0181804.
Golf balls having a high specific gravity layer are also known. For example, U.S. Pat. No. 9,155,937, discloses a multi-layer golf ball wherein the core includes a small, heavy inner core layer formed from a metal material dispersed in a thermoset or thermoplastic composition and having a relatively high specific gravity.
The present invention provides a novel golf ball construction, wherein a multi-layer core comprising a thermoset center, a thermoplastic intermediate core layer, and a thermoset outer core layer, and including at least one high specific gravity core layer, contributes to a golf ball having unique construction and performance properties.